The substance/substances initially involved in a chemical reaction are generally called reactants. Chemical reactions are usually characterized by a chemical change in the reactants, which then yields one or more products. Biomass gasification is an endothermic process that generates syngas; energy must be put into the process to drive the chemical reaction forward. Typically, this is performed by partially oxidizing (burning) the biomass itself. Between 30% and 40% of the biomass must be consumed to drive the process, and at the temperatures which the process is generally limited to (for efficiency reasons), conversion is typically limited, giving still lower yields and producing tars. Also, the chemical reactors in such traditional biorefineries are generally engineered to operate at constant conditions around the clock. In contrast, the proposed solar-driven biorefinery uses an external source of energy (solar) to provide the energy required for reaction, so none of the biomass need be consumed to achieve the conversion. This results in significantly higher yields of gallons of gasoline per biomass ton than previous technologies. As such, the energy source being used to drive the conversion is renewable and carbon free.